At the time
On April 26th we didn't know anything about the accident at the Chernobyl nuclear plant. I was very young and I was playing in the streets with other children. The next day, a Sunday, my parents wanted to visit our country house, but there were no buses to be had. 1200 buses had been sent to evacuate people from Pripyat and several hundred more to evacuate people from other villages close to the reactor. That evening the first official announcement was made on TV, it lasted only 14 seconds. My dad is a nuclear physicist, so the next day he brought a radiation detecting device home from work. It was as big as a suitcase. For the next two days radiation readings remained normal. At this time Sweden was already affected, but in Kiev all was still normal. The South wind saved us. Then on May 1st the wind changed direction, and that morning the reading at our home showed 1 milliroentgen per hour, which is 100 times greater than normal... I will never forget my father's face - he just grabbed me and my sister and put us on the train and sent us all off to my Grandmother's, safely away from the radiation.
I travel a lot and one of my favourite destinations leads North from Kiev, towards the so called Chernobyl "dead zone", which is 130kms from my home. Why my favourite? Because one can take long rides there on empty roads.
The people there all left and nature is blooming. There are beautiful woods and lakes.
In places where roads have not been travelled by trucks or army vehicles, they are in the same condition as they were 20 years ago - except for an occasional blade of grass or some tree that discovered a crack to spring through. Time does not ruin roads, so they may stay this way until they can be opened to normal traffic again... a few centuries from now.
Roentgens
To begin our journey, we must learn a little something about radiation. It is really very simple, and the device we use for measuring radiation levels is called a geiger counter . If you flick it on in Kiev, it will measure about 12-16 microroentgen per hour. In a typical city of Russia and America, it will read 10-12 microroentgen per hour. In the centre of many European cities it is 20 microR per hour, the radioactivity of the stone.
1,000 microroentgens equal one milliroentgen and 1,000 milliroentgens equal 1 roentgen. So one roentgen is 100,000 times the average radiation of a typical city. A dose of 500 roentgens is fatal to humans within five hours. Interestingly, it takes about 2 1/2 times that dosage to kill a chicken and over 100 times that to kill a cockroach.
This sort of radiation level can not be found in Chernobyl now. In the first days after the explosion, some places around the reactor were emitting 3,000-30,000 roentgens per hour. The firemen who were sent to put out the reactor fire were fried on the spot by gamma radiation. The remains of the reactor were entombed within an enormous steel and concrete sarcophagus, so it is now relatively safe to travel to the area - as long as one does not step off the roadway nor stop in wrong places...
The map above shows all our journey through the dead zone. Radiation went into the soil and is now in apples and mushrooms. It is not retained by asphalt, which makes rides through this area possible.
I have never had problems with the dosimeter guys, who man the checkpoints. They are experts, and if they found radiation on your vehicle, they gave it a chemical shower. I don't count those couple of times when "experts" tried to invent an excuse to give me a shower, because this had a lot more to do with physical biology than biological physics.
600 years.
On the Friday evening of April 25, 1986, the reactor crew at Chernobyl-4, prepared to run a test the next day to see how long the turbines would keep spinning and producing power if the electrical power supply went off line. This was a dangerous test, but it had been done before. As a part of the preparation, they disabled some critical control systems - including the automatic shutdown safety mechanisms.
Shortly after 1:00 AM on April 26, the flow of coolant water dropped and the power began to increase.
At 1:23 AM, the operator moved to shut down the reactor in its low power mode and a domino effect of previous errors caused a sharp power surge, triggering a tremendous steam explosion which blew off the 1000 ton cap on the nuclear containment vessel.
Some of the 211 control rods melted and then a second explosion, whose cause is still the subject of disagreement among experts, threw out fragments of the burning radioactive fuel core and allowed air to rush in - igniting several tons of graphite insulating blocks.
Once graphite starts to burn, it's almost impossible to extinguish. It took 9 days and 5000 tons of sand, boron, dolomite, clay and lead dropped from helicopters to put it out. The radiation was so intense that many of these brave pilots died.
It was this graphite fire that released most of the radiation into the atmosphere and troubling spikes in atmospheric radiation were measured as far as thousands of miles away.
These were inexcusable errors of design.
The causes of the accident are described as a fateful combination of human error and imperfect technology. Andrei Sakharov said, that the Chernobyl accident demonstrates that our system cannot manage modern technology.
In keeping with a long tradition of Soviet justice, they imprisoned several people who worked on that shift - regardless of their guilt. Twenty five from the shift died.
Radiation will stay in the Chernobyl area for tens of thousand of years, but humans may begin repopulating the area in about 600 years - give or take three centuries. The experts predict that, by then, the most dangerous elements will have disappeared - or been sufficiently diluted into the rest of the world's air, soil and water. If our government can somehow find the money and political will to finance the necessary scientific research, perhaps a way will be discovered to neutralise or clean up the contamination sooner. Otherwise, our distant descendents will have to wait until the radiation diminishes to a tolerable level. If we use the lowest scientific estimate, that will be 300 years from now...some scientists say it may be as long as 900 years.
I think it will be 300, but people often accuse me of being an optimist.
